The present invention generally relates to fixed leg platforms used in relatively shallow water for producing mineral resources, specifically oil and gas. The present invention more specifically relates to various embodiments of an apparatus and a method of installing an apparatus which protects wellheads from being struck from objects or equipment which may fall and impact the wellhead and production processing equipment.
Offshore hydrocarbon production in federal waters is regulated by the Minerals Management Service (the “MMS”). The MMS currently requires that wells be shut-in during various operations, including operations to install a drilling or work-over rig on the platform. Specifically, the applicable regulations require that all producing wells in the affected wallaby be shut in below the surface and at the wellhead when a drilling rig is moved between wells on the platform. The regulation also requires that wells be shut-in during rigging up and rigging down activities which occur within 500 feet of the affected platform or when a drilling unit is moved between wells on a platform or when a mobile offshore drilling unit moves within 500 feet of a platform.
This regulation recognizes that many heavy components are lifted over the wallaby and over the wellheads and production piping therein during the mobilization and moving of a drilling rig, presenting the risk that a heavy component may be dropped onto the production piping of a wellhead resulting in damage to the facilities and the possible release of hydrocarbons. The regulation further provides that once enough of the drilling rig, such as the superstructure, is over the well of interest, the wells may be returned to production. However, for a variety of reasons, the moving of a drilling rig may be delayed, resulting in a prolonged period that one or more producing wells are shut-in. For example, in rough seas the work boat transporting rig components may be delayed while waiting for smoother seas to deliver the components to the platform.
Shutting in producing wells is problematic for at least two reasons. First, production is lost or delayed when wells are shut-in. Bringing the wells back online can be time-consuming and may require substantial supervision to safely return the wells to production. Second, some wells are damaged from being shut-in, and do not always return to their previous flow rates after the wells are returned to production. For example, fine particles may be repositioned within the reservoir rock as a result of ebbing and surging flow associated with stopping and resuming of the production in a well. Loss of production is not only detrimental to the owner of the wells, but it also adversely impacts the royalties received by the federal government.
The MMS regulations grant the MMS District Supervisor some discretion in the shutting in of producing wells. The regulations provide that the MMS District Supervisor may approve departures from the shut-in requirement by making application to the District Supervisor. Among other information, the District Supervisor may consider platform structural data and point load calculations showing that the production process systems can withstand the impact of a dropped object. The District Supervisor may also consider a lift sequence plan which describes the order of the lifts, and the lift positioning on the platform deck relative to the wallaby areas and production processing equipment.